package com.zdxk.msgPush.websocket.netty.service;

import com.alibaba.fastjson.JSONObject;
import com.zdxk.msgPush.websocket.annotion.RequestHandler;
import com.zdxk.msgPush.websocket.annotion.RequestMappingProcessor;
import com.zdxk.msgPush.websocket.annotion.WebsocketRequestMapping;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.util.CharsetUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Parameter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static io.netty.handler.codec.http.HttpUtil.isKeepAlive;

public class NettyWebSocketHandler extends SimpleChannelInboundHandler<Object> {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    private int socketPort;

    private WebSocketServerHandshaker handshaker;

    public NettyWebSocketHandler(int socketPort){
        this.socketPort = socketPort;
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        logger.debug("收到消息："+msg);
        if (msg instanceof FullHttpRequest){
            //以http请求形式接入，但是走的是websocket
            handleHttpRequest(ctx, (FullHttpRequest) msg);
        }else if (msg instanceof WebSocketFrame){
            //处理websocket客户端的消息
            handlerWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        //添加连接
        logger.debug("客户端加入连接："+ctx.channel());
        ChannelSupervise.addChannel(ctx.channel());
//        Map<String,String> resMap = new HashMap<>();
//        resMap.put("websocketId",ctx.channel().id().asShortText());
//        ctx.write(new TextWebSocketFrame(JSONObject.toJSONString(resMap)));
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        //断开连接
        logger.debug("客户端断开连接："+ctx.channel());
        ChannelSupervise.removeChannel(ctx.channel());
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }
    private void handlerWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) throws InvocationTargetException, IllegalAccessException {
        // 判断是否关闭链路的指令
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
            return;
        }
        // 判断是否ping消息
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(
                    new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        // 本例程仅支持文本消息，不支持二进制消息
        if (!(frame instanceof TextWebSocketFrame)) {
            logger.debug("本例程仅支持文本消息，不支持二进制消息");
            throw new UnsupportedOperationException(String.format(
                    "%s frame types not supported", frame.getClass().getName()));
        }
        // 返回应答消息
        String request = ((TextWebSocketFrame) frame).text();
        logger.debug("服务端收到：" + request);
        JSONObject reqObj = JSONObject.parseObject(request);

        RequestHandler handler = RequestMappingProcessor.getRequestMappingMap().get(reqObj.getString("uri"));
        Object res = null;
        try{
            List<Object> methodParams = new ArrayList<>();
            JSONObject params = reqObj.getJSONObject("params");
            params.put("channelId",ctx.channel().id().asShortText());
            for(Parameter parameter : handler.method.getParameters()){
                Object param = params.get(parameter.getName());
                methodParams.add(param);
            }
            res = handler.method.invoke(handler.instance,methodParams.toArray());
        }catch (Exception e){
            logger.error("",e);
        }
        JSONObject status = new JSONObject();
        status.put("type","websocketStatus");
        status.put("status","connected");
        TextWebSocketFrame tws = new TextWebSocketFrame(status.toJSONString());

        // 群发
//        ChannelSupervise.send2All(tws);
        // 返回【谁发的发给谁】
         ctx.channel().writeAndFlush(tws);
    }
    /**
     * 唯一的一次http请求，用于创建websocket
     * */
    private void handleHttpRequest(ChannelHandlerContext ctx,
                                   FullHttpRequest req) {
        //要求Upgrade为websocket，过滤掉get/Post
        if (!req.decoderResult().isSuccess()
                || (!"websocket".equals(req.headers().get("Upgrade")))) {
            //若不是websocket方式，则创建BAD_REQUEST的req，返回给客户端
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(
                    HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(
                "ws://localhost:"+socketPort+"/websocket", null, false);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory
                    .sendUnsupportedVersionResponse(ctx.channel());
        } else {
            handshaker.handshake(ctx.channel(), req);
        }
    }
    /**
     * 拒绝不合法的请求，并返回错误信息
     * */
    private static void sendHttpResponse(ChannelHandlerContext ctx,
                                         FullHttpRequest req, DefaultFullHttpResponse res) {
        // 返回应答给客户端
        if (res.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(),
                    CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        // 如果是非Keep-Alive，关闭连接
        if (!isKeepAlive(req) || res.status().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
}
